Study On Rock Model And Soft Rock Cutting Simulation Based On Discrete Element Method

With the increasing of subway and high-speed railway construction,the demand for engineering equipment in industry is also increasing.The working efficiency and service life of rock breaking equipment are of great significance to the actual engineering construction.Therefore,the optimization of the structure of rock breaking equipment has become a hot research topic.In the process of actual rock breaking,cutters and rocks,sandstones and sandy soil directly affect each other.Therefore,the study of rock mechanical properties and failure criteria has important scientific significance and practical value to the research and development of rock breaking equipment structure and to the promotion of work efficiency and work safety.Discrete Element Method(DEM)has been widely used to simulate the flow of bulk materials and the fracture process of brittle materials because it is easy to deal with the interaction between elements.However,when using DEM to simulate brittle materials such as rock,it is necessary to check the mechanical parameters of DEM.The verification process is very time consuming and labor intensive,and when the conditions change,such as the size of the element changes,the micro parameters need to be verified again.Therefore,it is of great practical value to find a fast and reasonable discrete element model method.Therefore,in this paper,the regular arrangement cube model is used to simulate the rock,and the soft rock cutting process is simulated and analyzed,and the cutter parameters are optimized.The main contents of this paper are as follows:Firstly,the secondary development was performed on the basis of EDEM software,and the regular arrangement cube model was programmed.Then,the compression process of elastic block is simulated to verify the validity of this model.The strain of elastic block is obtained by the geometric equation,and the stress-strain curve is obtained.The relationship between the slope of stress-strain curve and Young's modulus of elastic block at different time is compared.The relationship between the strain ratio of expansion direction and compression direction and Poisson's ratio of elastic block at different time is compared.Consistency is used to evaluate the feasibility of the model in the elastic range,and to test the correctness and validity of the regular permutation discrete element model and its implementation program in the elastic range.Then,in order to simulate the rock breaking behavior during the cutting process,a damage model was added on the basis of the regularly arranged discrete element model,that is,when the stress between the discrete elements reached the limit value,the elastic connection keys between the discrete elements were converted into contact keys and programmed by programming implement the process.The failure processes of rock under Brazilian disc and uniaxial compression tests are numerically simulated.The validity of the regular arrangement discrete element model,the failure model and implementation program are verified by comparing the simulated crack form and maximum load with the corresponding experimental results.Finally,based on the above verification results of the regular arrangement discrete element model,a discrete element rock model is established to simulate the rock cutting processes,and the effects of structures and cutting parameters on cutting performance and cutting efficiency are investigated numerically.